Leader follower architecture.
Leader maintains a map of its followers with their addresses.
Leader runs on :3000.
Follower runs on random ports.
When follower boots up, it establishes a new TCP connection with Leader and Leader registers the follower by storing its details.
When a SET, DEL command is given, leader ensures that all the followers are in sync with the given command.
SET command can be paired up with a TTL(in seconds), after which entry will be removed from the store

$ make leader
$ make follower

Enhancements

Have a response timeout from the followers so that leader can know when a follower has went down.
GET queries should be forwarded to the followers by the leader. (Optional, bring in a reverse proxy(handwritten) which can distribute the load in a Round-Robin fashion)
Implement a consensus algorithm which can elect a leader amongst themselves, when a leader fails to send a heartbeat to its followers.

Working sample through CLI

Screenshot from 2023-01-30 10-21-06